Numbers 13:19

Are they open. Targum [Onkelos] translates, הַבְּפַצְחִין (“whether in open cities”), cities that are exposed and open, for lack of a wall.

Is it good. With excellent, prolific wells and deep water shelves.

what the land is in which they dwell, whether good or bad; what cities they inhabit, whether they live in towns that are open or walled;

WHETHER IT IS GOOD OR BAD. Rabbi Abraham ibn Ezra commented [that the meaning thereof is that they are to see] “if the Land is good, namely that its air is good, and its waters are good.” Then Moses continued, whether it is fat, meaning “capable of producing wheat” and many fruits.
The correct interpretation is that whether it is ‘good’ includes all good things, and in the word ra’ah [or ‘bad’] are included all evils. [If so, the question arises why Moses continued with the apparently superfluous command to find out whether the Land is fat or lean, since it is already included in the phrases good and bad?] It is possible, however, that a good land is fruitful and its fruits are fat, and it produces fat products such as balsam and oil, dates and figs and similar things. But [it is also possible] that it is good and yet lean, and always needs rain, and must be hoed and fertilized very much, and its fruits have a tendency to be dry although they are better and last longer than the fat ones. In such a land are to be found very many “lean” fruits, such as nuts, almonds, apples, carobs and fruits of the forests. Thus [by saying that the spies are to ascertain whether the Land is fat or lean Moses] meant “whether it is a fat land, as valleys are, or a lean land like the mountains.” Onkelos, however, translated [whether it is fat or lean as] “whether it is rich or poor,” for there are countries whose inhabitants are rich because of the low prices prevalent among them, and their neighbors trade with them in all the good things found among them, and there are some countries whose inhabitants are dependent upon their neighbors and their inhabitants are of small power, although they are good [lands] and not at all bad.
‘And be ye of good courage’, and bring [of the fruit of the Land]. This means that they are not to be afraid when taking of the fruit of the Land that they might be recognized by the people as spies.

ומה הארץ אשר הוא יושב, seeing that the words ומה הארץ of which we said that they referred to the parts of the country which the invaders would face immediately, an area not populated, now the Torah refers to other parts of the land of Canaan which were fully populated. Hence the words:

בארץ אשר הם יושבים בה הטובה היא אם רעה, if the land produces ample harvests so that the invaders would be able to supply themselves with locally grown produce instead of bringing the food supply with them.

הבמחנים, whether the inhabitants live in open cities or in fortresses. All this kind of information was needed so that they would know to take with them the tools needed to lay siege to fortresses, for instance.

הטובה היא, was the water supply plentiful and not contaminated. Moses had stressed in Deuteronomy 8,7 that G’d was bringing the people to a location which was “good” in the sense that it possessed brooks and rivers with pure water.

הבמחנים, if they lived in open cities, a sign that they felt secure, not expecting any war,

אם במבצרים, or in walled, fortified towns, suggesting that the inhabitants were afraid of being invaded. Compare Devorah’s song in Judges 5,7 where she bemoans the fact that her people had ceased to live in open cities.